My piano teacher lent me some books that are very old and expensive. My piano has a little dip down that holds the music, but when I turn the page, the bottom of the page drags along the top of the dip and folds/ripples the page. I don't want to damage these books, so how would I fix this?

My dad improvised a shelf-extension for my piano with a bent sheet of aluminum. You could make one with a slight rise at the edge instead of a lip. Cost of materials is quite low, but an aluminum bender is a very large and pricey tool.